A driver assistance system having the function of lane departure warning (LDW) in which the driver of a vehicle is warned about leaving a lane by acoustic, visual, haptic warning signals or any combination thereof, has also in the meantime become commercially available for the field of commercial vehicles. The LKS (lane keeping support) function, which actively supports the driver in keeping the vehicle in the lane through directed guidance torques, i.e., intervention into the steering system of the vehicle, is of great practical importance.
A driver assistance system having an LKS function is described in Naab, Reichert: “Driver Assistance Systems for Lateral and Longitudinal Vehicle Guidance—Heading Control and Active Cruise Support,” AVEC 94.
German Patent Application No. DE 101 37 292 A1 describes a method for operating a driver assistance system of a vehicle, in particular a motor vehicle, having servo-supported steering, which is characterized by the following steps: detecting or estimating ambient data of a preferably instantaneous traffic situation; detecting or estimating preferably instantaneous movement data of the vehicle; comparing the detected or estimated ambient data with the movement data of the vehicle; changing the support of a steering action in accordance with the comparison.
Special characteristics of the LKS function offering the driver support in keeping in the lane only in an edge area of the lane should be mass produced in the not-too-distant future. These systems do not intervene in a corridor around the center of the lane. This means that the driver must execute the guidance of the vehicle himself through steering movements within this corridor. To implement the LKS function, the driver assistance system includes an arrangement for detecting the course of the lane. This arrangement usually includes video sensors for detecting lane markings. The course of the lane in front of the vehicle and the relative position of the vehicle with respect to the lane are determined from two generally parallel lane markings. In situations in which no parallel lane markings are detectable, the LKS function is deactivated as a precautionary measure. Such a situation occurs, for example, in locations where a lane is widened. With such a lane widening, the road surface is widened and the single lane opens into multiple lanes.